Want! Want!

[Griffin NoName]

http://news.bbc.co.uk/1/hi/programmes/click_online/9708468.stm

<sigh> looks like we have to wait 2-3 years

[Aggie]

One potential issue in the US: The most likely early adopters of the electric car will be California, and they are major power importers already.  BC Hydro has been installing smart meters here, and power bills have been jumping, because they are now bidding us against California during prime energy use times (we export hydroelectricity from this province, most years). Either shift your habits, or pay the price.

[Bob in a quantum-state-of-faith]

One potential issue in the US: The most likely early adopters of the electric car will be California, and they are major power importers already.  BC Hydro has been installing smart meters here, and power bills have been jumping, because they are now bidding us against California during prime energy use times (we export hydroelectricity from this province, most years). Either shift your habits, or pay the price.

Power-trading is a commodity like anything else.  And smart meters are enabling that- what?

You actually believed the story (as told by the power companies) that the smart meter would benefit the consumer?

One of the things that makes this more palatable, though, are smart appliances-- especially ones that consume mass quantities of electricity--like clothes dryers and dishwashers (using the heat-dry cycle).  A smart appliance can be programmed to query the smart meter, and ask it what's the going rate-- and be told when the cheap rates begin (and end), and adjust their operating cycle accordingly.  So you put your clothes in your dryer as usual, you set it to start whenever the power goes cheap, and you ignore it until morning-- during the night sometime, it get's the "go ahead" and runs its full cycle at the cheaper rate.  Same for the automatic dishwasher-- load it up after supper, set it to run whenever, and next morning?  Dishes are done-- ran during the cheap-rate period in the wee hours of the morning.

You could even tell your appliances to not interfere with each other-- to keep the total load low, the dryer runs, while the dishwasher patiently waits for it's turn....

... lovely.

Now..... to coordinate with all your neighbors, to keep the total neighborhood demand low... let's see: Smith will start her's at 12am, and Jones' will get the 1am slot, and McAllen's get the 2am....

.... this is all possible with smart meters:  the power company knows the demand of each resident, and at what time, for how long too.

"Let's see:  it's 8'o'clock on Friday.  The Smedlaps always turn on their Jacuzzi at 8, better dial it up a notch for sector 1K2B....  and the Mendalls always cook a pizza at 9... and over at the O'Donnell's, their 11 kids fire up all 6 X-boxes at 10"

[Aggie]

I never believe any of those stories.

Ayuh, and there's speculation that it may not be impossible to hack the signals to tell exactly what's going on with other people in your neighbourhoods.  Burglary rings could have great fun with this.

I wonder what the power company would do if one stuck a Faraday cage around the meter/antenna? Or if 'squirrels' chewed the cables to the antenna?  Probably fine you for the former.

I wonder to what degree the hybrid-car factor will apply to smart appliances.... you too can save money on energy, but only if you pay more in the original purchase price than you're likely to recoup for many years, vs sticking with a more modest energy-efficient standard appliance.  The alternative for some appliances is to just buy a cheap manual timer to run things (although this isn't as easy in the case of high-use three-phase appliances).

[Bob in a quantum-state-of-faith]

Yes, simple mechanical (manual) timers are easily adapted to most of the non-electronic appliances like dishwashers and electric clothes dryers.   

But the more modern appliances have digital controls, and if you remove power (as with a simple timer) when it's restored, the appliance starts up in idle mode... not gonna work.   You'd have to hack the inner workings somehow... voiding the warranty in the process.

I've even seen demonstrations of refrigerators that try to limit the power-useage during peak hours (refrigerators gobble up huge amounts of power-- not all at once, but they never stop.. and it adds up prodigiously).

What really gets me, though?  Is you put your heat-producing refrigerator inside your house-- then you use another "refrigerator" to remove that heat and all the rest-- the AC unit... wouldn't it make more sense, at least in the summer, to funnel some outside air across the refrigerator's coils, and dump the now hotter air back outside?  Yes... yes it would.. but nobody bothers with that...

... meh.

Of course, during the winter, the extra heat is welcome, but here in Oklahomer, the winter's just not that long-- so it does not even out even a little-- 3 months of welcome extra heat, offeset by 9 months of unwelcome extra heat... I really ought to built a duct and test it out...



As for 3 phase appliances?  Those are more rare than lawyers practicing for free, here in the States... even in commercial settings.

[Griffin NoName]

Hang about, that link was to develpment of new chargers - not costings/meters etc. Did we do a topic drift?

Also, what are we going to do when everything is "smart"? We'll need a new word for new things. To be honest I am already a bit sick of smart.

[Bob in a quantum-state-of-faith]

Yeah, sometimes "smart" means "they think they know better than you-- so bend over and prepare for the inevetable ***ing by the Giant MegaCorp"....

... meh.

But not always-- sometimes "smart" can mean adaptable and flexible-- able to cope with rapidly changing conditions that would leave a "dumb" appliance near-useless.

[Sibling Zono (anon1mat0)]

It should be smarter, because there is usually some improvement but still lots of room to improve more.

[Bob in a quantum-state-of-faith]

It should be smarter, because there is usually some improvement but still lots of room to improve more.

How else can they get you to buy next year's model?

What?

You planned to keep it for 17 years, like the last one?  Seriously? 

Are you trying to ruin the economy? 

[Aggie]

As for 3 phase appliances?  Those are more rare than lawyers practicing for free, here in the States... even in commercial settings.

Yes, I was muddled with the 240V outlets, which are three prong but not three-phase. I've only used three-phase for heavy duty water pumps running off diesel generators. Bit of a brain fart.


The point of the electrical timers was intended exactly for those who have stuck with the erm, 'classics' in the way of appliances.   Presumably all the other smart-wotzits will be programmable via an app on your smartphone or tablet. Amazing; ten years ago we were probably thinking that we'd program all our appliances of the future via a central control panel, Star Trek style, but now it's just going to be a piece of software on your pocket computer.

Regarding refrigerators, it actually makes sense (heat-wise) to mount the compressor at the top of the fridge, so that convection will dissipate the heat without passing it around the outside of the box.  The smaller the temperature gradient across the insulated walls, the more efficient the fridge is. Even better... if you can do a permanent install, mount the compressor separate from the body of the fridge, and perhaps find a way to recover the waste heat using a heat exchanger, to preheat the intake stream of your hot water tank. Higher efficiency, no issues with counterproductive heat in the summer.

A more modest approach is to put your main storage freezer in the basement, which is the coolest place in the house, or if you are in a secure area, put it under a covered area on the north side of your house.  It'll do very little work in the winter, and in the summer it will still be relatively cool and shady there.

[Sibling DavidH]

This 120V / 240V split phase power in the USA seems totally weird to a European.  OK, heavy loads draw too much current at 120V, but why not use the higher voltage for everything?

[Bob in a quantum-state-of-faith]

I totally love your refrigerator/hot-water machine, Aggie-- you ought to patent that idea, it's beautiful.  

As for split refrigerators?  I do commercial work occasionally-- and for the unnamed fast-food franchise, they do exactly that:  they split the system-- inside the insulated box (built to order-- it's a walk-in refrig/freezer (two compartments) the compressor is on the roof, along with the heat-getting-rid-of-panel (condenser).  

But they also have a giant commercial hot-water tank, with a circulating pump for instant-on hot water-- and yes, they do insulate the pipes-- so there are three pipes going to each sink:  cold, hot-supply and hot-return (both insulated).

But if they had a heat-loop to capture some of that wasted heat from the freezer's output?  Wondermous-- the natural gas fire would be set to a higher temperature, such that it only came on, if there was insufficient heat-gain from the freezer's output.   Would save them boat-loads of operational cash-money.  And since they already have the circulation pump.... a simple heat-capture loop, with a thermostatic valve controlling the loop:  if heat is available on the roof, open the valve, let the water circulate.  If the output on the roof is lower temperature than the water already?  Close the valve.  Let the air dump the excess heat.  Simple.

I love it.

---------------------------------

David:  it's worse than that-- before Westinghouse "standardized" electric power, back in the day, there used to be a fight between him and Edison-- Edison advocated direct current, at much lower voltages, some as low as 6 volts, but 12, 24 or even 60 volts was not unheard of for power-- all DC.  

Westinghouse won, with A/C, and had initially set the volts to an arbitrary 100v.  120v was a little later, likely due to pushing an initial volts of 120 to achieve a delivered volts of 100 at the other end.  They discovered in those days, that if your wire run was short enough?  You only needed one wire-- let the path "return" via the earth itself-- and stringing a single wire was way cheaper than stringing two...  and the A/C would "float" with the ground, using that one wire.

Later still, this practice was discarded, and two wires were used-- and later still, three, for multiphase.  Finally, in modern systems?  There are 4:  the 4th one being a ground-return or "neutral".

But the 2nd wire was added to increase capacity:  it was at the opposite phase of the A/C cycle, and quadrupled the carrying load of the single wire that way--- but the effective, additive volts of the two opposite-phase wires, each being pushed at 120v, gave you 240v.     But since they still referenced to ground?  A single leg, referenced to the literal ground, would give you 120v.

In the early days, each "half" would go to a different, adjacent customer's house.  It wasn't until later, that they started putting both legs in-- and adding a dedicated 3rd "neutral" leg up to the house itself, leaving the earth-reference back at the power-pole.

3 phase came later-- I suspect it was an attempt to add more capacity, without re-stringing the entire run-- add a 3rd conductor, and again greatly increase the total output more than by 1/3, by shifting the phase of the 3rd wire.   It's called a "balanced load" as the theoretical load-return doesn't actually exist (A/C-- oscillating back and forth, the current "floats") -- the energy is all "used up" by the load.  

In the 50's it was discovered that you really needed an actual ground, tied to the ground, to bleed off minor imbalances-- or else these would build up and spark, starting fires...  

... and there you have it.

It wasn't as if anyone sat down and planned it--they really didn't understand exactly the total consequences-- but they did understand stringing one fewer wires was cheaper than stringing two (initially), and cheaper almost always wins out in the end.

One of the happy consequences of using A/C over D/C?  Is you get much less transfer-corrosion effects at your various electrical junction points-- the current is rapidly pushing one way, then pushing back the other way (in and out, if you will).  This has the effect of reducing the migration of dissimilar metals from one point to the other, which greatly helps reduce corrosion.  In DC, you can get this phenomena, which leads to bad connections eventually.

Another beneficial side-effect of A/C versus D/C:   if a human accidentally gets in contact with A/C, the muscle spasms (not unlike a shiver) tend to force you to let go (at lower voltages) than D/C which tends to make you "lock-on" (driving your muscles to contract as hard as they can).  So it is ever so slightly safer-- a dubious "fact" that Westinghouse exploited to the detriment of Edison's DC efforts.

Now, as I described this, it was all hunky-dory, and processed from one to the next-- which is hardly the case at all.  The actual history was a boat-load of trial-and-error, backwards "progress" and other things.

But competition eventually led to the modern practices and policies.  Accompanied by not a few deaths and injuries along the way, as humans learned how to wrangle this thing called "electricity".

I have no idea why Europe went strictly to the full two-phase 240v myself-- that's missing from my education.   Sorry.  

Oh, and I left out a couple of critical facts, too:

With DC current, you start out with a given volts, say 60.   And at each step in the line, each junction, each length of wire?  The volts drops-- such that, by the end (customer's house) you might have 50v (on a slow day).  You might have 40v.  You might have only 6v (if everyone has their lights on, say).  No way to tell at the point of origin, really, what the final voltages will turn out to be.   But no real way to regulate this, back in those days of vacuum tubes and wire-wound resistors.

You could not easily change the voltages at all, back in those days.   In fact?  You pretty much had to power an electric motor connected to a generator of the desired voltages.... with a loss of efficiency of better than 50%.

But with A/C?  You used the back-and-forth "motion" of the current, and the latent magnetic effect of soft-iron.   That is, if you put a magnetic field into a chunk of soft iron, and then remove it, the magnetic effect takes a bit to go away-- it's not immediate.   But you can easily change voltages with A/C, using this effect:  to go down, from say 100v to 50v?  You put 100 turns of wire around one side of an iron ring, and 50 turns around the other half, and in comes 100v and out goes 50v at pretty good efficiencies too.   You can go the other way, by reversing the set-up. 

Add in this:  higher voltages are less susceptible to power losses due to long wire-runs, than lower volts.

So you generate your volts at many, many thousands of volts-- makes the generators cheaper too (smaller wires).  Send this kilovolt power along the main trunks, greatly reducing the power-loss due to wire resistance. 

Then, at your customer's house?  You step it down to the desired voltages, using a simple power transformer.

You simply could not do that with DC back in Edison's day.  You just could not get there from here, effectively.

Which is the main reason AC one the electricity 'wars'

[Sibling DavidH]

I have no idea why Europe went strictly to the full two-phase 240v

No, we all use 3-phase, though an ordinary dwelling-house uses only 1 phase (plus earth and neutral).  Each house along the road is supposed to be connected to the next phase from next door: Red - Yellow - Blue ...

But our village hall used to be a workshop and has 3 phases.  Wiring faults between phases can cause loud bangs.    When I've wired in new sockets and lights, I've  had to label each one with its phase when updating the plan.

[Bluenose]

Same here in Aus.  I suspect that one reason for using 240 V is the reduction in Ohmic loss.  For the same power transmission 240 V reduces losses by a factor of 4.

[Bob in a quantum-state-of-faith]

Same here in Aus.  I suspect that one reason for using 240 V is the reduction in Ohmic loss.  For the same power transmission 240 V reduces losses by a factor of 4.

You can also send more power over a given set of wires-- or you may reduce the size of the wires for the same power-load.

Either way, it's cheaper overall to stick with 240v than a lower value.

I also suspect that there are safety factors too-- 240v typically is not referenced to ground, with the actual current/loads, whereas 120v typically is-- one "side" of the conductor circuit is referenced to ground (allegedly at a zero float current-- but ground faults do happen, creating a hazardous condition), whereas the other "side" is called "hot" or has potential voltage (120v) with respect to the ground (literal or figuratively, depending on the circumstance).

However, many 240v circuits do have a ground potential, but at 1/2 the voltage (120v), at least here in the USA, they do.

There really is no reason to do that, though, and if you didn't do that?  It would be overall safer.... alas, it isn't so, and we are bound by Tradition!  It's Tradition--dammit!

... meh.

[Sibling Zono (anon1mat0)]

All this discussion brings a question for me, as superconducting lines are coming I had heard somewhere that those work for better DC, is that correct? And what voltages work better with superconducting lines?

[Griffin NoName]

Same here in Aus.  I suspect that one reason for using 240 V is the reduction in Ohmic loss.  For the same power transmission 240 V reduces losses by a factor of 4.

Edison - Tesla
AC
DC
Maybe it's just caused by whoever wins such battles.

EDIT cross posted with Zono's post

[Bob in a quantum-state-of-faith]

All this discussion brings a question for me, as superconducting lines are coming I had heard somewhere that those work for better DC, is that correct? And what voltages work better with superconducting lines?

I do not think superconducting wires "care" one way or another-- what these things have, which is weird, is zero resistance to current-flow (or as near zero as makes no difference).

If you remember Ohm's Law?  It's R= I*V, where I is current (amps) and V is volts and R is resistance.

However.... since we are not permitted to divide by zero.... it complicates things immensely, and you cannot (I would presume) use this to calculate what happens with a superconductor.

One of the weirder things you can do with superconductors?   Is "store" electricity more or less indefinitely.   How?

Easy:  construct a large (really large) electromagnet using superconducting wire-- but, instead of attaching the free ends to a power supply (as you would expect to do), connect them together...  in a continuous loop ....  Next, surround that (or interweave it) with a second set of wires (superconducting or not-- doesn't really matter, but superconducting would be more efficient, and you have to super-cool the other wires anyway...).

These wires' ends, you bring out to your power grid-- this is the load/power supply.  

To store electricity?  You charge up the inner-loop of superconducting wire to a really high gauss (magnetic strength) amount-- say a few million times earth's.   You do this, by sending current into your "charge" circuit-- the ones who's ends you brought out of the superconducting assembly.   So long as the inner loop does not break, the current within it will continue to flow around and around like an endless electronic racetrack-- and the magnetic field will be immense.   Theoretically, you could store an infinite amount here-- but practically, you are limited by your "in and out" wire capacities.   And the overall strength of the whole thing-- too strong a magnetic field would bend things and it'd tear itself to shreds.

To get your charge out?  Apply a load to the wires that come out of the assembly-- and you should get out as much power as you had put in-- in fact, regulating it to come out in a controlled fashion would be your biggest hurdle (as opposed to all at once in a giant lightning bolt..... that would be .. bad.)

All you need to do, to maintain your stored charge, would be to keep everything at super-cold superconducting temperatures....

... it sounds too good to be true, doesn't it?  

As I said-- superconducting is weird.


Edit:  I don't think the volts matter, either-- see Ohm's law... since resistence is zero, in theory, the volts would become infinite, right?  ... right?   

.... it's really, really weird....   

[Roland Deschain]

I remember the R=I*V triangle from school. Superconductivity is really weird, and there is some great research into exotic materials which is looking to get the [metaphorical] holy grail of room temperature superconductors. If the grid was replaced with something like this, it would revolutionise electricity supply, for sure. I remember reading in New Scientist years ago about replacing the grid with cold superconducting materials, and how this was possible to achieve then with enough money pumped into it. Unfortunately, with private commerce running the show in many places, this will not happen any time soon.

[Sibling Zono (anon1mat0)]

I think the argument for DC superconductors was to avoid the inevitable change to it at the end of the line (electric motors can work efficiently on AC but most electric and electronic appliances use DC internally).
--
The superconducting accumulator is a great idea, it reminded me of the flywheel accumulators being developed that had the problem of exotic materials needed to allow them to rotate at very high angular speeds. This would work in an equivalent way but with no moving parts, excellent!

[Bob in a quantum-state-of-faith]

Efficiencies of mechanical conversions from electricity vary a great deal-- depending on a variety of things.

But for simple mechanical rotational power, there are few systems that can beat an AC induction motor.   The speed is directly proportional to two things:  the Hertz (or cycles per second) of the AC itself, and the number of windings in the outer, induction coil(s).   That's it.    There is no need for a speed controller, if a fixed speed (or a limited number of speeds) meets your requirement.

What's more?  The power you can apply to these things is only limited by the capacity of the windings' in the wire-- for a 1/4 horsepower AC induction motor and a 1/2 horsepower motor are exactly the same-- except for the size (diameter/guage) of the internal wiring! 

This is because in an AC induction motor?  It automatically "pulls" as much power as it need to meet the load you place on it's output shaft(s).    It's actually kinda cool that way-- if you have variable load requirements?  You size the motor to meet the highest expected continuous load, and then don't worry about it.  If the load is less than maximum?  No big deal, the motor automatically draws less current.

I love these things-- they were invented/developed over a hundred years ago, and the basic engineering has only changed in the minute details.   And the only moving part, is not electrically charged at all! 

It works like this:  since there is AC power coming into the outer windings (coils)?  This rapidly changing current creates rapidly changing magnetic fields.   Such fields, if you allow soft iron nearby, will induce electrical current-flow, in spite of there not really being a full-circle path-- the frequency is high, so the actual flow is minuscule in length anyway.

But once you have current-flow? You have magnetic fields-- identical to the ones that are inducing the current in the first place. Since the core is free to move?  (it rotates)  It will try to move away from the opposing field, and be attracted towards the opposite field (on the opposite side of a conventional, two-coil design).   In a single-coil design, all you have is the same-type field.  But there are 3 coil, 4 coil, multiple-intertwined coil designs too, but they all work basically the same way).

Now as the inner magnetic field starts to move, the coil's field collapses and reverses-- if this happened at too low a frequency, the inner iron core would simply vibrate back and forth in an oscillation.   But the reversal happens so quickly, and the lag of the core is always behind the actual field, so the same-polarity-opposing fields quickly becomes opposite-attraction fields, pulling the inner core around it's shaft, but before it can get there and "lock", the field reverses yet again.   Round and around it goes.

In classical designs the motor could easily rotate left as well as right-- there was no electromechanical reason to do one or the other-- in fact, on some very early designs, an external handle would start a slow rotation by hand, before you apply power-- and it would continue to rotate at the designed speed on it's one after that.

To overcome this, start-up capacitors were added-- this caused a slight "delay" in part of the windings-- effectively changing a simple winding into a complex one, with part of the winding being partway around the rotational circumference-- this forced the inner core to rotate in one direction only, as when both coils were energized, one was wound one-way, and the capacitor's windings go the opposite way, thus you always begin with matching--same-polarity (push) and opposite-reverse-polarity (pull) magnetic fields with respect to the inner iron core.   A simple reversal of the two wires on the capacitor's coil, and it would rotate in the opposite direction-- handy, if you need bi-directional motors.   (The capacitor acts like a little accumulator-battery in the circuit, storing up, then releasing after a minute delay, the AC current-- this causes the energy to be released slightly behind the main coil's, effectively giving a slightly out-of-phase current to the starting windings.)

To complicate things more?   The inner iron core can be straight-line, essentially parallel to the rotational shaft, or it can be twisted with respect to the shaft, like a very shallow screw's threads, only less than a quarter-turn along it's whole length.   This twist increases the start-up torque, at a minor sacrifice of the running torque.

Then there are multi-phase motors-- each phase acting like an additional cylinder in a radial piston engine, greatly multiplying the delivered power to the shaft.   No starting capacitor needed, no twisted inner core either-- three-phase naturally (due to 3 out-of-phase AC currents) "rotates" the magnetic field around the inner core, depending on how many turns of wire in each winding-- and, obviously, you can have multiple windings for each of the three phases too.


Bottom line is this-- the efficiency of an induction wound AC motor is only limited by the purity of the iron core, and the resistance of it's conductors.   For resistive wire, such as copper, wastes some of the energy as simple heat-- if you got rid of all resistance?

In theory, the induction motor could achieve 100% efficiency.....!   Of course, you'd need a core that was also 100% efficient as well--

....!!

So supercool the whole thing, making everything super-conducting, right?   

In theory, this would be 100% efficient-- and the Universe would explode or something, because you'd violate the 2nd law of thermodynamics....



In the classic design, the inter

[Griffin NoName]

I don't think the volts matter,

They do if you touch an overhead cable.

[Bluenose]

I also suspect that there are safety factors too-- 240v typically is not referenced to ground, with the actual current/loads, whereas 120v typically is-- one "side" of the conductor circuit is referenced to ground (allegedly at a zero float current-- but ground faults do happen, creating a hazardous condition), whereas the other "side" is called "hot" or has potential voltage (120v) with respect to the ground (literal or figuratively, depending on the circumstance).

However, many 240v circuits do have a ground potential, but at 1/2 the voltage (120v), at least here in the USA, they do.

In Aus and the UK, the 240 V is completely different to what you describe.  We run with three phases, each 120 degrees from the next.  The 240 V is measured from the neutral, which is tied to ground at the meterbox at each supply point.  The phase to phase voltage is 415 V.  Supply cabling is via 4 wires, the three phases plus neutral (which is usually thinner than each phase wire, since it only carries difference current between the phases - if all the phase loads were equal it would carry no current).  Each house is supplied from the alternate phases in turn as they run down the street.  Generally homes have only one phase, but occasionally you will get two or even less commonly all three phases into a home.  Larger commercial and industrial sites, of course, usually have a three phase supply. Three phase plugs are much more robust than domestic ones and look completely different (at least in OZ).